ByIdrees Ali and Yeganeh Torbati, ReutersApril 26, 2016

Smoke rises as people flee their homes during clashes between Iraqi security forces and members of the Islamic State group in Hit, Iraq, 85 miles (140 kilometers) west of Baghdad, Monday, April 4, 2016. Families, many with small children and elderly relatives, said they walked for hours Monday through desert littered with roadside bombs to escape airstrikes and clashes.

Washington — The number of foreign fighters joining the Islamic State militant group in Iraq and Syria has decreased sharply in the past year to about 200 a month, a U.S. military official said on Tuesday.

That is a drastic decline from about a year ago when between 1,500 and 2,000 foreign fighters were joining the group in Iraq and Syria each month, said Air Force Major General Peter Gersten, deputy commander for operations and intelligence for the U.S.-led coalition, during a news briefing from Baghdad.

Earlier this month, the State Department said the number of Islamic State fighters in Iraq and Syria was lower than at any time in the past two years.

Syria has become the main global incubator for a new generation of militants as Islamic State recruited as many 31,000 foreign fighters in the past 18 months, according to a report published by a former British spy chief last year.

Gersten added that the number of fighters defecting from Islamic State was increasing as well, but he did not give a specific number.

"We're seeing a fracture in their morale, we're seeing their inability to pay, we're seeing the inability to fight, we're watching them try to leave Daesh in every single way," Gersten said, using an Arabic acronym for Islamic State.

The Washington Times reports that since October, US airstrikes – dubbed Operation Tidal Wave II – have undermined the Islamic State's financing by hitting oil fields, banks and cash houses.

U.S. intelligence estimated the group’s financial losses due to the operation was between $300 to $800 million, Gen. Gersten said during a briefing from Baghdad.

“The Tidal Wave strikes led us to their bank sources, their bank sources have led us to their distribution sources, and their distribution sources has led us to their foreign fighters,” he added.

On Monday, President Obama announcement that 250 US Special Operations Forces will be sent to Syria, adding to some 50 US forces already on the ground.

Last fall, Mr. Obama sent 50 special operators to Syria as trainers as “a proof of concept of sorts,” says Melissa Dalton, a former intelligence analyst for the Defense Intelligence Agency. The goal was to see if the United States could use the training to gain traction with Kurdish fighters and Arab Sunnis on the ground, she says.

It “seems to reflect that this proof of concept works,” adds Ms. Dalton. “There’s been some positive momentum built up, with the idea now being, ‘OK, if we expand that out a bit further – multiply the amount of trainers in the country – then perhaps we can multiply the effects.' ”